A typical bicycle includes a front fork. The fork is typically comprised of spaced left and right fork blades, a crown and a steerer tube. The proximal ends of the fork blades are secured to the crown and extend downwardly therefrom. The blades-each include a slot at its respective distal end to receive and secure the end of an axle of a front wheel therein. The steerer tube extends generally upwardly from a distal end, which is secured to the center of the crown in between the proximal ends of the fork blades. The crown acts to secure the blades and the steerer tube together. Variations are known. For instance, some front forks have a single mono blade to which a front wheel connects. In other variations, the typically tubular blades are bent or curved inwardly at their proximal ends and welded or otherwise secured directly to the steerer tube eliminating a distinct crown. Suspension forks are also well known wherein multi-part blade assemblies include sprung and/or dampened sliders. Other types of suspension forks are known wherein the steerer tube assemblies are sprung and/or dampened.
The steerer tube is configured by way of a headset to be rotatably received in a head tube of a corresponding bicycle frame. Most typically, the top end of the steerer tube extends above and out of the top of the frame's head tube wherein a stem can be secured there-around. A handlebar is then attached to the stem, which allows a rider to steer the associated bicycle in use. It is to be appreciated that some bikes use handlebars and stems that are combined in a single integral unit.
Forks are typically manufactured with long steerer tubes that are subsequently cut to fit a bicycle frame based on the length of the frame's head tube, the stack height of an associated headset, the length of the stem clamp, and the desired height of the stem to properly fit the bicycle to the particular body dimensions of the rider. If the steerer tube is mistakenly cut too short, it cannot be used in the intended frame and will have to be discarded or retained for possible later use in another frame with a shorter head tube. In practice many mechanics cut the steerer tube a little bit longer than necessary and use spacers placed underneath or above the stem clamp to vary the height of the stem relative to the frame. Typically, the amount of adjustment is limited to less than an inch, which may not be sufficient in some circumstances.